Grading of follicular lymphoma in cytological samples

Commentary on small-volume biopsy of follicular lymphoma: Practical issues in the molecular era

Follicular lymphoma (FL) is a common subtype of non-Hodgkin lymphoma derived from germinal center B-cells. Small-volume biopsies (SVBs), including fine-needle aspiration, needle core biopsy, and cell blocks, are often used for the assessment of patients with FL. Recently, Fitzpatrick et al. found that additional biopsies were frequently needed to supplement SVB for the initial diagnosis of FL. However, regardless of the type of SVB used, additional biopsies were usually not necessary for assessments for transformed or recurrent FL. Their multi-institutional study reflects the fact that SVB may be sufficient for clinical decision-making in these medical settings, although surgical excision is the gold standard for a definitive diagnosis of FL. With ancillary tests and advances in molecular testing, SVB has become increasingly popular and helpful, although there are practical limitations.

Small volume biopsy diagnostic yield at initial diagnosis versus recurrence/transformation of follicular lymphoma: A retrospective Cyto-Heme Interinstitutional Collaborative study

BACKGROUND

Few studies have evaluated diagnostic yield of small volume biopsies (SVB) for the diagnosis and management of follicular lymphoma (FL).

METHODS

The authors performed a multi-institutional retrospective analysis of SVBs including fine-needle aspiration (FNA) and needle core biopsy (NCB) for initial FL diagnosis and suspected recurrence or transformation of FL. A total of 676 workups beginning with SVB were assessed for the mean number of biopsies per workup, the proportion of workups requiring multiple biopsies, and the proportion with a complete diagnosis including grade, on initial biopsy.

RESULTS

Compared to workups performed for question transformation/recurrence, those done for initial FL diagnosis were significantly more likely to require multiple biopsies (p < .01), had a higher mean number of biopsies per workup (1.7 vs. 1.1, absolute standardized difference = 1.1), and a lower complete diagnosis rate at initial biopsy (39% vs. 56%). At initial FL diagnosis, NCB +/- FNA was associated with fewer biopsies per workup compared to FNA +/- CB (1.2 vs. 1.9), fewer workups requiring multiple biopsies (23% vs. 83%), and a higher complete diagnosis rate (71% vs. 18%). In contrast, during assessment for transformation/recurrence, NCB and FNA showed a similar mean number of biopsies per workup (1.2 vs. 1.2) and few workups required multiple biopsies (6% vs. 19%).

CONCLUSIONS

SVB at initial FL diagnosis often required additional biopsies to establish a complete diagnosis. In contrast, when assessing for transformed/recurrent FL, additional biopsies were generally not obtained regardless of SVB type, suggesting that in these clinical settings SVB may be sufficient for clinical decision-making.